For breadboarding, you should build a breadboard adapter or use female-to-male DuPont wires to link the module to the breadboard. Also note that there are two versions of the ESP-01 now available — ...

The second issue is that the ESP-01 is a 3.3 V device, which can be annoying if everything else in the circuit is running on 5 V. To get around this, the adapter includes an SPX3819 regulator and ...